1. Field of the Invention
This invention relates, in general, to a pendulum gate valve and more particularly to a pendulum gate valve for creating a vacuum tight seal to a vacuum chamber and methods for its use.
2. Description of Related Art
In the semiconductor industry, automated silicon wafer substrate handling systems are utilized to move wafers into and out of process modules that perform various operations on the wafers, such as vapor deposition, ionization, etching, etc. These handling systems are commonly referred to as cluster tools.
The processes performed on the wafers are done within vacuum chambers, and the cluster platforms and associated equipment are housed in “clean” rooms, the environments of which are strictly controlled. Vacuum chambers and clean rooms are utilized in order to prevent the smallest of particles from being introduced into the wafer matrices. In addition, the wafer processing equipment of cluster tools is designed for low particulate generation through millions of cycles of operation. To achieve ultrapure fabrication techniques, processing equipment is employed that has a minimum of moving parts, and to further prevent particle contamination, machine components are properly isolated and sealed.
With clean rooms, space utilization is of utmost importance, as the costs for operating a clean room are extremely expensive. Accordingly, there is an advantage in providing more efficient equipment in less space, in order to lower manufacturing costs.
Gate valves are commonly employed to provide vacuum seals at numerous locations between modular integrated processing equipment. For example, gate valves are positioned between wafer cassette modules and central handling modules, and between central handling modules and process modules. Gate valves open to allow transfer of wafers between modules, and close to seal off modules so that vacuum controlled processes may be performed within the modules.
Present gate valve assemblies generally include moving parts which are subject to sliding and/or reciprocal metal-to-metal contact within the valve chamber. Such contact contributes to particulate generation within the valve chamber which may contaminate the vacuum chambers of process modules to which the present gate valve assemblies are attached.
What is needed is pendulum gate valve which overcomes the above and other disadvantages of known pendulum gate valves.